The following chronic toxicity/carcinogenicity and initiation/promotion studies of 1,2-Dihydro-2,2,4- trimethylquinoline(TMQ) are to be conducted. 1. A 104-week skin paint study in F344 rats and B6C3F1 mice which involves 3 dose levels plus controls, including groups of animals receiving 5 or 3 applications/week. Complete histopathologic evaluation is to be done. 2. A 26-week initiation/promotion study using male F344 rats with the option to conduct a 72-week study. The 26-week study involves 7 treatment groups with a determination of the number and size of GGT foci. Histopathology is limited to the liver. The optional 72-week study involves 7 treatment groups with interim sacrifices at 26 and 52 weeks. Groups will be treated for 72 weeks or will be treated for up to 52 weeks, treatment withdrawn and the animals held until the end of the study (72 weeks). All groups will have limited histopathologic and GGT evaluations performed. 3. A 52-week initiation/promotion study in female Sencar mice. A preliminary dose finding study is to be conducted for 21 days. The 52-week study involves 13 treatment groups using 3 dose levels of TMQ. Histopathology is limited to the skin and liver.